Name

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ZERO_CROSS

Purpose

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This function returns the number of zero crossings in a given time
series.

Category

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Time Series Analysis

Calling Sequence

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Result = ZERO_CROSS( Data )

Inputs

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Data: A vector of type integer or floating point.

Keyword Parameters

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SUBTRACT_MEAN: If set, the global mean is substracted from the time
series before analysis. The default is not to do so.

Optional Outputs

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POS: Returns the locations in Data just before the zero crossings.

Outputs

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Result: Returns the number of zero crossings.

Uses

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MEAN.pro

Procedure

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This function iteratively compares the signs of neighbouring points.

Example

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Define a vector.
data = [-1,2,3,-1,2]
Find the number of zero crossings.
result = zero_cross( data )
The result should be 2.

Modification History

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  Written by: Daithi A. Stone (stoned@atm.ox.ac.uk), 2003-10-09.